As population increases, the desire for more electrical power is also generally increasing. Demand for this power typically varies during the course of a day with afternoon and early evening hours generally being the time of peak demand with later night and very early morning hours generally being the time of lowest demand for power. However, power generation systems need to meet both the lowest and highest demand systems for efficiently delivering power at the various demand levels.
One system attempts to solve this problem by storing energy generated during off-peak demand hours for use during peak demand hours. This system is called an Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) system and is shown in FIG. 1 as part of a power generation system 2. The power generation system 2 is now generally described by following the path of the air flow. Initially in step 3a, air is taken into an axial compressor 4 and compressed during which the air is put under pressure and undergoes an increase in temperature. This air is exhausted in step 3b, and undergoes cooling at the Intercooler 6 to be cooled to the desired temperature for further compression. The air flow is then entered in step 3c to a first radial compressor 8. The air is then compressed by the first radial compressor 8, exits the first radial compressor 8 and in step 3d enters a second radial compressor 10 for further compression.
The air flow then goes, in step 3e, from the second radial compressor 10 to an energy storage unit, e.g., a Thermal Energy Store 12. The hot compressed air from the second radial compressor 10 is then cooled by the Thermal Energy Store 12. The heat energy is stored in the Thermal Energy Store 12 for future use and any water that is generated by the cooling process is drained off. The cooled compressed air is then sent to a Safety Cooler 14 in step 3f, where the air is further cooled prior to being sent in step 3g to a storage facility, e.g., cavern 16. This storage of the compressed air in the cavern 16 and the storage of the energy in the Thermal Energy Store 12 typically occurs during non-peak demand operation of the power generation system 2.
When the demand for power from the power generation system 2 increases to a desired point, energy output can be increased by releasing the stored compressed air back into the system to drive an expander 18, e.g., a turbine. For example, the cavern 16 releases some of the stored compressed air, in step 3h, to the Thermal Energy Store 12 for heating. Heat energy is transferred from the Thermal Energy Store 12 to the compressed air and the heated compressed air flows to a particle filter 20 in step 3i. The heated compressed air then flows, in step 3j, to an expansion section of turbine 18. During expansion the air cools and undergoes a pressure drop while producing the work which drives the shaft 26 which in turn spins a portion of a generator 30 for power generation. After expansion the air flows from the turbine 18 to an air outlet 22 in step 3k, typically for release to atmosphere. Power generation system 2 can also include a shaft 24 for the compressors, a gear box 28 and a motor 32.
While the system shown in FIG. 1 does allow for storing energy for use during peak demand hours, it can be appreciated that power needs are going to grow and finding ways to meet the growing demand is desirable.
Accordingly, systems and methods for improving efficiency in power generation systems are desirable.